Why exercise is special
The flipside of a hyper-active evolutionary background is that the human body decompensates without movement. Booth et al. summarised in a long review that physical inactivity is an independent cause of more than 35 chronic conditions — from cardiovascular disease and type 2 diabetes to dementia and certain cancers.1
Pedersen and Saltin went further with a systematic review describing the evidence for exercise as therapy across 26 different chronic diseases. The short answer: for almost all of them, it's at least as effective as first-line medication, often with better side-effect profiles.2
How much and what kind
The international guideline (ACSM, WHO) is clear: at least 150 minutes of moderate-intensity aerobic activity per week (or 75 minutes vigorous), plus two resistance-training sessions covering all major muscle groups.3 That's a floor; more delivers more within wide margins.
Importantly, the intensity curve isn't linear. The biggest mortality gains sit in the step from 'nothing' to 'something' — going from 0 to 60 minutes per week wins relatively more than going from 300 to 360. That makes 'starting' more important than 'being perfect'.
VO₂max, fitness and strength
VO₂max — maximal oxygen uptake — is one of the strongest predictors of all-cause mortality we have. The JAMA Network Open study by Mandsager showed that high cardiorespiratory fitness is associated with markedly lower 10-year mortality risk, with an effect on the same order as smoking (in the opposite direction).4
Muscle mass and strength complete the picture. Sarcopenia (age-related muscle loss) is an independent risk factor for early mortality, falls, fractures and loss of independence.5 Resistance training is the only intervention that reliably reverses it — two sessions per week is enough for most people to build or preserve significantly.
Exercise for brain and mood
Exercise is one of the best-supported interventions for mental health. Aerobic training produces acute improvements in mood, reduces depression and anxiety symptoms, and is associated with greater hippocampus volume — a region central to memory and cognition.7
The mechanism is broad: raised BDNF (a brain-derived growth factor), better sleep, lower inflammation, better insulin sensitivity. For desk workers: prolonged sitting is an independent mortality risk, and most of that excess risk disappears once you hit sufficient daily activity.8 Even short 'vigorous intermittent lifestyle physical activity' bursts (a few minutes hard, multiple times a day) associate with markedly lower mortality in recent cohort data.6
What you can measure
Three measurements that move with your training state without needing a lab: resting heart rate (drops with cardiovascular improvement), HRV (rises), and a wearable's VO₂max estimate. Apple Watch, Garmin and similar devices give good estimates for week-on-week trends.
On the blood side, HbA1c, triglycerides and HDL respond particularly well; with resistance training, ferritin and ALP shift too. The Optimize Baseline measures these together, so your training routine doesn't just feel like it's working — you can see it on the markers that matter.
What you can do yourself
The short answer: get from zero to something, then build consistently. For most people that's 150 minutes of moderate-intensity per week plus two short resistance sessions — and the effect is larger than they expect. Start with what you can actually sustain (a daily 20-30 minute walk plus two 30-minute resistance sessions) and ramp up gradually.
Three practical principles do the heavy lifting:
- 01Make it sticky — pick a slot in your week that's non-negotiable and stack it onto something you already do (after the school drop-off, before breakfast).
- 02Count the small bursts too — a few minutes of stairs or cycling hard pays off surprisingly well in cohort data.6
- 03Make your training state visible — resting heart rate, HRV and a wearable's VO₂max estimate move with your fitness, and seeing it work keeps you going.
When to involve a physician
Before a large step-up in intensity if you have known heart or vascular disease, have been inactive for a long time and are over 45 (women) or 35 (men) with risk factors, or get chest pain, dizziness or breathlessness during or after exercise. For most healthy adults a gradual start is safe without prior medical screening.